INTRATHYROID CYSTS OF THYROGLOSSAL DUCT ORIGIN

Thyroglossal duet cysts develop from a persistent portion of the thyro glossal tract and have been described as occurring anywhere from the b ase of the tongue to the manubrium. We present two patients who presen ted with a cystic thyroid nodule due to an intrathyroid thyroglossal d uct cyst. A fine-needle aspiration biopsy was performed, which reveale d benign squamous cells. Upon exploration, the first patient was found to have a 2-cm cyst within the thyroid isthmus, and in the second pat ient, a l-cm cyst was found in the right thyroid lobe. Pathologic anal ysis revealed the cyst to be lined by a squamous epithelium consistent with a thyroglossal duct cyst. The lesions were completely surrounded by normal thyroid tissue. There was no evidence of a remnant of the t hyroglossal duct extending from the thyroid in the region of the cyst. Both patients were treated by thyroid lobectomy and isthmusectomy and have remained without evidence of recurrence. Intrathyroid thyrogloss al duct cysts should be included in the differential of patients with cystic thyroid lesions. Fine-needle aspiration revealing benign squamo us cells is usually diagnostic and may detect an occult carcinoma aris ing within the cyst. Surgical resection is curative and should include a Sistrunk procedure if a thyroglossal duct tract is present.